08-11-08Carbon dioxide levels in the atmosphere may already be in danger zone according to a search by a group of 10 scientists from United States, United Kingdom and France.

The study of the group of 10 scientists published in Open Atmospheric Science Journal says that atmospheric carbon dioxide must be re3duced to below the level that already exists in order to avert climate disasters.

The authors of the study assert that to maintain a planet similar to that on which civilization developed, an optimum CO2 level would be less than 350 ppm. This is a dramatic change from most previous studies, which suggested a danger level for CO2 is likely to be 450 ppm or higher.

Atmospheric CO2 is currently 385 parts per million (ppm) and is increasing by about 2 ppm each year from the burning of fossil fuels (coal, oil, and gas) and from the burning of forests.

The authors of the paper include scientists from Yale University, the NASA/Goddard Institute for Space Studies and Columbia University Earth Institute, the University of Sheffield (UK), CEA-CNRS-Universite de Versaille (France), Boston University, Wesleyan University and from the University of California at Santa Cruz.

"This work and other recent publications suggest that we have reached CO2 levels that compromise the stability of the polar ice sheets," said author Mark Pagani, Yale professor of geology and geophysics. "How fast ice sheets and sea level will respond are still poorly understood, but given the potential size of the disaster, I think it's best not to learn this lesson firsthand."